Fatty acid methyl esters (FAME) are a type offatty acid ester that are derived bytransesterification offats withmethanol. The molecules inbiodiesel are primarily FAME, usually obtained fromvegetable oils bytransesterification. They are used to produce detergents and biodiesel.[1] FAME are typically produced by analkali-catalyzed reaction between fats and methanol in the presence of base such as sodium hydroxide,sodium methoxide[2] or potassium hydroxide. One reason for using FAME (fatty acid methyl esters) in biodiesel production, rather than free fatty acids, is to mitigate the potential corrosion they can cause to metals of engines, production facilities, and related infrastructure. While free fatty acids are only mildly acidic, over time they can lead to cumulative corrosion. In contrast, their esters, such as FAME, are less corrosive and therefore preferred for biodiesel production. As an improved quality, FAMEs also usually have about 12-15 units highercetane number than their unesterified counterparts.[3]
FAMEs are colorless compounds with melting points near room temperature.
| FAME | formula | Registry number | refractive index | density (g/cm3) | melting point (°C) | boiling point (°C) |
|---|---|---|---|---|---|---|
| Methyl laurate | CH3(CH2)10CO2CH3 | 111-82-0 | 1.4301 | 0.8702 | 5.2 | 267 |
| Methyl myristate | CH3(CH2)12CO2CH3 | 124-10-7 | - | 0.8671 | 17.8 | 295 |
| Methyl palmitate | CH3(CH2)14CO2CH3 | 112-39-0 | 1.4310 | - | 29.5 | 417 |
| Methyl stearate | CH3(CH2)16CO2CH3 | 112-61-8 | 1.45740 | 0.83 | 40 | 443 |
| Methyl oleate | CH3(CH2)6CH=CH(CH2)5CO2CH3 | 112-62-9 | 112- | 0.8739 | -19.9 | - |
Microorganisms have diverse and sometimes distinctive FAME profiles, the basis of "microbial fingerprinting". Aftertriglycerides,fatty acids and certain otherlipids of some cultured microbes are transesterified or esterified, the resulting FAMEs can be analyzed withgas chromatography.[4] These profiles can be used as a tool for microbial source tracking (MST) to identify pathological bacteria strains[5] and for characterizing new species of bacteria.
For example, a profile created fromcultured bacteria from some water sample can be compared to a profile of known pathological bacteria to find out if the water is polluted by feces or not.[5]
In June 2022, Polycyclopropanated fatty acid methyl ester (POP-FAME) fuels were biosynthesized fromStreptomyces coelicolor bacteria, which have energy densities of more than 50MJ/L larger than the most widely used aviation and rocket fuels.[6]